Display systems for displaying alphanumeric characters have been available commercially for several years. An example of such a display is the 3270 Information Display System manufactured by International Business Machines Corporation which is described in Systems Manual GA27-2749-5, File No. S360/S370/Sc-09 entitled "IBM 3270 Information Display System Component Description".
Alphanumeric display systems are normally designed to display Latin type languages such as English, German, French and other European languages where characters are written and read from left to right. However, Middle East countries use Hebrew, Farsi or Arabic languages which are written and read in the reverse direction from right to left. As Latin type languages are also used commercially in these countries, there is a requirement for a display system in which entered words can be displayed either in a normal left to right mode for Latin type languages or in a reverse right to left mode for Middle East languages.
One known method of reversing a display is to reverse the scan coils driving the CRT causing a raster to be produced which scans from right to left. Also the characters must be individually reversed so that they are displayed in normal orientation. This prior art method involved permanent rewiring and is not particularly suitable for the selective normal or reversed operation.